198 A BOOK OF INSECTS 



in crevices of the bark, during the winter. At the first 

 approach of spring it spins its cocoon and changes to the 

 pupa from which the adult moth emerges in due course. 

 The so-called " maggots," which are often found when a 

 pea-pod is split open, are usually the caterpillars of a 

 small moth (GrapholitJia pisana), closely allied to the 

 codlin moth. These issue from the pod when they are 

 full-fed, and turn to pupa? in the soil, where they remain 

 throughout the winter. The caterpillars of certain small 

 moths of the same widely distributed family ( Tortricidce) 

 have achieved fame under the guise of "jumping beans." 

 There are at least two species of these insects, found 

 in the United States and Mexico. 



Probably the reader has suffered the unpleasant ex- 

 perience of cracking a filbert or cob nut, only to find 

 within a fat white grub and a much-damaged kernel; 

 and it may have occurred to him to wonder how the culprit 

 obtained access to its snug quarters. The explanation is 

 really quite simple. Its parent, the nut-weevil (Balamnus 

 nucum), bores a hole with her long rostrum in a young 

 nut, and inserts her egg. As the nut develops and the 

 shell hardens, all trace of the injury is obliterated. But 

 the grub within feeds sumptuously upon the kernel. In 

 the autumn it bores a small round hole through the shell, 

 drops to the ground, hibernates beneath the soil, and 

 changes to a pupa in the early spring. The pea beetle 

 (Bruchus pisi) is another seed - destroying insect. The 

 female lays her eggs on the pods when they are very 

 young, and the grub on hatching bores through the pod 

 and into a pea, where it finds sufficient nourishment for 

 its development. It eventually pupates in the pea, having 

 first eaten its way to the outer coat, so that when the 

 adult beetle matures it has only to break its way through 

 a thin skin. An allied species of Bruchus is said to 



